Evaluation of proton density fat fraction (PDFF) obtained from a vendor-neutral MRI sequence and MRQuantif software.

OBJECTIVE: To validate the proton density fat fraction (PDFF) obtained by the MRQuantif software from 2D chemical shift encoded MR (CSE-MR) data in comparison with the histological steatosis data. METHODS: This study, pooling data from 3 prospective studies spread over time between January 2007 and July 2020, analyzed 445 patients who underwent 2D CSE-MR and liver biopsy. MR derived liver iron concentration (MR-LIC) and PDFF was calculated using the MRQuantif software. The histological standard steatosis score (SS) served as reference. In order to get a value more comparable to PDFF, histomorphometry fat fraction (HFF) were centrally determined for 281 patients. Spearman correlation and the Bland and Altman method were used for comparison. RESULTS: Strong correlations were found between PDFF and SS (rs = 0.84, p < 0.001) or HFF (rs = 0.87, p < 0.001). Spearman's coefficients increased to 0.88 (n = 324) and 0.94 (n = 202) when selecting only the patients without liver iron overload. The Bland and Altman analysis between PDFF and HFF found a mean bias of 5.4% ± 5.7 [95% CI 4.7, 6.1]. The mean bias was 4.7% ± 3.7 [95% CI 4.2, 5.3] and 7.1% ± 8.8 [95% CI 5.2, 9.0] for the patients without and with liver iron overload, respectively. CONCLUSION: The PDFF obtained by MRQuantif from a 2D CSE-MR sequence is highly correlated with the steatosis score and very close to the fat fraction estimated by histomorphometry. Liver iron overload reduced the performance of steatosis quantification and joint quantification is recommended. This device-independent method can be particularly useful for multicenter studies. CLINICAL RELEVANCE STATEMENT: The quantification of liver steatosis using a vendor-neutral 2D chemical-shift MR sequence, processed by MRQuantif, is well correlated to steatosis score and histomorphometric fat fraction obtained from biopsy, whatever the magnetic field and the MR device used. KEY POINTS: • The PDFF measured by MRQuantif from 2D CSE-MR sequence data is highly correlated to hepatic steatosis. • Steatosis quantification performance is reduced in case of significant hepatic iron overload. • This vendor-neutral method may allow consistent estimation of PDFF in multicenter studies.

Surgical management of adhesive small bowel obstruction: Is it still mandatory to wait? - An update.

Small bowel obstruction syndromes (SBO) represent one of the main causes of emergency admission for surgical abdominal pain. The 2018 Bologna Guidelines (Ten Broek et al. 2018) recommend non-operative management at the outset if there are no signs of severity; surgery is proposed after 72h for the 20-30% of patients who fail medical management. However, these recommendations were based on old studies published at a time when laparoscopic surgery was not commonplace and when diagnostic capabilities (particularly for establishing etiology) were less developed than they are today. Additionally, the advent and development of laparoscopy and enhanced rehabilitation after surgery have led to a decrease in surgical morbidity. These guidelines are therefore now debated and several recent publications have encouraged urgent or semi-urgent surgical management for patients presenting for SBO in order to reduce morbidity, mortality, duration of hospitalization and costs, and to improve the feasibility of therapeutic laparoscopy. Prompt surgical management could also reduce the risk of recurrent small bowel obstructions. This model for early surgical management probably cannot be applied to all patients. It therefore seems important to select those patients at risk for failure of medical treatment and to identify those in whom the probability of successful laparoscopy is high. New radiological tools should allow better selection in the future. At the present time, the indications for early surgery "within 24h" should be emphasized.

[Impact of partial nephrectomy in a hybrid operating room on the activity of kidney cancer surgery]. / Évaluation de l'utilisation de la salle hybride sur l'activité de chirurgie en cancérologie rénale.

INTRODUCTION: Partial nephrectomy (NP) after embolization of tumor vessels (NPESH) in a hybrid room combines embolization of tumor vessels and enucleation of the tumor under laparoscopy in the same operative time. The purpose of this study was to assess the impact of the use of NPESH in the management of patients treated with surgery for a localized kidney tumor. MATERIAL AND METHODS: Using the uroCCR database, we included all consecutive patients operated in a university hospital for localized kidney tumor. From 2011 to May 2015, patients were treated by Standard Partial Nephrectomy (NPS) Laparoscopic or Open and from May 2015 to May 2019 by NPESH. We evaluated characteristics of patients, tumors, perioperative data and complications. These data were compared by Student and Khi2 tests. RESULTS: 87 NPS were performed during Period 1 and 137 NPS were performed during period 2. The ASA score of patients undergoing NPESH was higher than NPS (P<0.0001). The tumor complexity and median tumor size were similar in the two groups (P=0.852 and P=0.48). The complication rate for NPS and NPESH was 55.2% and 33.6% (P=0.002). There were less severe complications in the NEPSH group (P=0.012). The median length of stay was 8 and 4 days for the NPS and NPESH groups (P<0.0001). Positive surgical margins were 2 (2.3%) and 6 (4.6%) for the NPS and NPESH group (P=0.713). DISCUSSION: NPESH is an efficient technique compared to NPS. It seems to be an interesting alternative to limit renal ischemia, complication rate and length of stay for the management of localized kidney tumors.

Utility of enhanced CT for patients with suspected uncomplicated renal colic and no acute findings on non-enhanced CT.

AIM: To evaluate the utility of contrast-enhanced computed tomography (CECT) for patients with suspected uncomplicated renal colic (URC) and no abnormalities on non-enhanced computed tomography (NECT). MATERIALS AND METHODS: The hospital institutional review board and ethics committee approved this retrospective study with a waiver of informed consent. Between January 2016 and April 2017, all consecutive adult patients who consulted at the adult Emergency Department (ED) with suspected URC and who had undergone both NECT and CECT were included retrospectively. The primary endpoint was prevalence of CECT-only diagnosis without acute findings on NECT. The risk factors for an acute finding were identified by logistic regression analysis. RESULTS: Among 126 patients with suspected URC, 12 were excluded. Among the 76 patients with no acute findings on NECT, CECT led to find acute lesions in 14/76 (18%) cases, but only 2/76 (3%) resulted in a change of management. Predictive factors of abnormal finding on CECT were: low renal clearance and high leukocyte count with OR 0.96 (95% confidence interval [CI]: 0.93-0.99), p=0.0189 and OR 5.79 (95% CI: 1.55-21.64), p=0.0091, respectively. CONCLUSIONS: In most cases, NECT is sufficient for screening patients with suspected URC. If leucocytosis and low renal function are present, stronger consideration may be given to CECT.

Diagnosis of focal liver lesions from ultrasound using deep learning.

PURPOSE: The purpose of this study was to create an algorithm that simultaneously detects and characterizes (benign vs. malignant) focal liver lesion (FLL) using deep learning. MATERIALS AND METHODS: We trained our algorithm on a dataset proposed during a data challenge organized at the 2018 Journées Francophones de Radiologie. The dataset was composed of 367 two-dimensional ultrasound images from 367 individual livers, captured at various institutions. The algorithm was guided using an attention mechanism with annotations made by a radiologist. The algorithm was then tested on a new data set from 177 patients. RESULTS: The models reached mean ROC-AUC scores of 0.935 for FLL detection and 0.916 for FLL characterization over three shuffled three-fold cross-validations performed with the training data. On the new dataset of 177 patients, our models reached a weighted mean ROC-AUC scores of 0.891 for seven different tasks. CONCLUSION: This study that uses a supervised-attention mechanism focused on FLL detection and characterization from liver ultrasound images. This method could prove to be highly relevant for medical imaging once validated on a larger independent cohort.

Burned bodies: post-mortem computed tomography, an essential tool for modern forensic medicine.

Currently, post-mortem computed tomography (PMCT) has become an accessible and contemporary tool for forensic investigations. In the case of burn victims, it provides specific semiologies requiring a prudent understanding to differentiate between the normal post-mortem changes from heat-related changes. The aim of this pictorial essay is to provide to the radiologist the keys to establish complete and focused reports in cases of PMCT of burn victims. Thus, the radiologist must discern all the contextual divergences with the forensic history, and must be able to report all the relevant elements to answer to the forensic pathologist the following questions: Are there tomographic features that could help to identify the victim? Is there evidence of remains of biological fluids in liquid form available for toxicological analysis and DNA sampling? Is there another obvious cause of death than heat-related lesions, especially metallic foreign bodies of ballistic origin? Finally, what are the characteristic burn-related injuries seen on the corpse that should be sought during the autopsy? TEACHING POINTS: • CT is highly useful to find features permitting the identification of a severely burned body. • PMCT is a major asset in gunshot injuries to depict ballistic foreign bodies in the burned cadavers. • CT is able to recognise accessible blood for tests versus heat clot (air-crescent sign). • Heat-related fractures are easily differentiated from traumatic fractures. • Epidural collections with a subdural appearance are typical heat-related head lesions.

Suspicious liver nodule in chronic liver disease: Usefulness of a second biopsy.

PURPOSE: To assess the usefulness of a second biopsy when the first one was inconclusive in patients with a liver nodule found during the follow-up for chronic liver disease. MATERIALS AND METHODS: Among 381 patients (544 nodules) included in a prospective study designed to evaluate the accuracy of imaging for the diagnosis of small hepatocellular carcinoma (HCC) in chronic liver disease, 254 nodules were biopsied. The following histological results were considered as conclusive: HCC, dysplastic or regenerative nodule, and other identified tumors (benign or malignant). For nodules with inconclusive results (e.g. fibrosis or no definite focal lesion), a second biopsy was suggested, but was not mandatory. RESULTS: A total of 242 patients (194 men, 48 women; mean age, 61.9±9.5 [SD]; range: 40.2-89.0years) with 254 nodules underwent a first biopsy. Mean nodule diameter was 19.2±5.4mm (range: 10-33mm). The first biopsy was conclusive in 189/254 nodules (74.4%): 157 HCCs (83.1%), 11 regenerative nodules (5.8%), 10 dysplastic nodules (5.3%), 3 cholangiocarcinomas (1.6%), and 8 other tumors (4.2%). Among the 65 nodules for which the first biopsy was inconclusive, a second biopsy was performed for 17 nodules in 16 patients within 6 months of the first one. It was conclusive in 13/17 nodules (76.5%): 10 HCCs (76.9%), 2 dysplastic nodules (15.4%), and 1 other tumor (7.7%). In 4/17 nodules (23.5%), no definitive diagnosis could be provided. CONCLUSION: The diagnostic yield of a second biopsy of a suspicious lesion suggestive of HCC in chronic liver disease is not decreased compared to the first one. Repeated biopsy after a first negative one could be an alternative option to the follow-up of patients with chronic liver disease.

Liver fibrosis, cirrhosis, and cirrhosis-related nodules: Imaging diagnosis and surveillance.

Although biological scores and elastography continue to yield the best results, imaging retains a crucial role in the diagnosis of liver fibrosis and cirrhosis. First, digestive symptoms or biological liver test abnormalities often lead the referring physician to request an abdominal ultrasound, and with an experienced operator, accuracy of ultrasound can reach 85% for the diagnosis of severe fibrosis or cirrhosis. Second, imaging could lead to discovery of nonsymptomatic fibrosis or cirrhosis, with an estimated prevalence of 0.5-2.8% in the population. After diagnosis, imaging is central in the follow-up of cirrhosis. It is used to detect worsening of portal hypertension and hepatocellular carcinoma (HCC). Because many nodules are present in a cirrhotic liver, familiarity with the features of HCC can facilitate noninvasive diagnosis and early and accurate treatment.

Diagnosis of hepatocellular carcinoma: An update on international guidelines.

Imaging is essential for the successful management of patients with or at risk of developing hepatocellular carcinoma (HCC). If ultrasound remains the key screening modality, computed tomography and magnetic resonance imaging (MRI) can play a major role in the characterization and noninvasive diagnosis of nodules in patients at risk of developing HCC. Each technique has succeeded in adapting to the wide histological spectrum of focal liver lesions. In this review, we discuss recent advancements in imaging techniques and evaluation - notably diffusion-weighted imaging, contrast-enhanced ultrasound, and liver-specific MRI contrast agents - as well as their addition to international guidelines and reporting systems such as the Liver imaging reporting and data system (LI-RADS).

CT findings of complications after abdominal wall repair with prosthetic mesh.

Postoperative complications following prosthetic mesh repair are relatively rare and depend on the type and location of prosthetic mesh. They include abscess, hematoma, seroma, fistula, bowel obstruction, mesh retraction, granuloma and recurrent hernia. Computed tomography (CT) is the imaging examination of choice for the diagnosis of such complications. This pictorial review illustrates the CT presentation of the most and less common postoperative complications following prosthetic mesh repair of the abdominal wall.

Failure of Conservative Treatment of Acute Diverticulitis with Extradigestive Air.

BACKGROUND: Medical management for perforated diverticulitis without abscess or peritonitis (PDwAP) has a success rate of 40-70%. Identifying patients with a risk of medical treatment failure would improve outcomes. The aim of this study was to identify the risk factors for failure of medical treatment in patients admitted with PDwAP. METHODS: This multicenter retrospective observational study included all consecutive patients admitted for PDwAP and not surgically treated over a 7-year period. Peritonitis classified on the Hinchey scale was excluded. Potential clinical, biological and radiological risk factors for medical treatment failure were collected and compared between the group of patient with a failure of medical treatment (F) and the group in which treatment did not fail. Data were collected at referral. RESULTS: Ninety-one patients were included, and 29 had a failure of treatment (31.9%). The median heart rate was different between the two groups (p < 0.001), at approximately 100/min in the F group. A blood level of C-reactive protein (CRP) ≥150 mg/mL was associated with a higher rate of failure (p = 0.021), but it was not confirmed in multivariate analysis. Pneumoperitoneum ≥5 mm and intraperitoneal liquid located in the pouch of Douglas were more likely to be present in the F group (respectively, p = 0.001 and p < 0.001). A multivariate analysis showed independent risk factors as being the highest pneumoperitoneum diameter >5 mm (OR 5.193; p = 0.015) and peritoneal fluid location in the pouch of Douglas (OR 4.103; p = 0.036). CONCLUSION: The severity of sepsis (tachycardia and CRP ≥150 mg/mL) and of imaging signs (pneumoperitoneum ≥5 mm and peritoneal fluid in the pouch of Douglas) were risk factors for medical treatment failure of PDwAP requiring special supervision so as not to lose time in undertaking surgical management.

Liver fibrosis diagnosis by blood test and elastography in chronic hepatitis C: agreement or combination?

BACKGROUND: In chronic hepatitis C, the European Association for the Study of the Liver and the Asociacion Latinoamericana para el Estudio del Higado recommend performing transient elastography plus a blood test to diagnose significant fibrosis; test concordance confirms the diagnosis. AIM: To validate this rule and improve it by combining a blood test, FibroMeter (virus second generation, Echosens, Paris, France) and transient elastography (constitutive tests) into a single combined test, as suggested by the American Association for the Study of Liver Diseases and the Infectious Diseases Society of America. METHODS: A total of 1199 patients were included in an exploratory set (HCV, n = 679) or in two validation sets (HCV ± HIV, HBV, n = 520). Accuracy was mainly evaluated by correct diagnosis rate for severe fibrosis (pathological Metavir F ≥ 3, primary outcome) by classical test scores or a fibrosis classification, reflecting Metavir staging, as a function of test concordance. RESULTS: Score accuracy: there were no significant differences between the blood test (75.7%), elastography (79.1%) and the combined test (79.4%) (P = 0.066); the score accuracy of each test was significantly (P < 0.001) decreased in discordant vs. concordant tests. Classification accuracy: combined test accuracy (91.7%) was significantly (P < 0.001) increased vs. the blood test (84.1%) and elastography (88.2%); accuracy of each constitutive test was significantly (P < 0.001) decreased in discordant vs. concordant tests but not with combined test: 89.0 vs. 92.7% (P = 0.118). Multivariate analysis for accuracy showed an interaction between concordance and fibrosis level: in the 1% of patients with full classification discordance and severe fibrosis, non-invasive tests were unreliable. The advantage of combined test classification was confirmed in the validation sets. CONCLUSIONS: The concordance recommendation is validated. A combined test, expressed in classification instead of score, improves this rule and validates the recommendation of a combined test, avoiding 99% of biopsies, and offering precise staging.

Evaluation of unenhanced post-mortem computed tomography to detect chest injuries in violent death.

PURPOSE: The aim of this study was to assess the performances of unenhanced post-mortem computed tomography (CT) to detect thoracic injuries in violent death. MATERIALS AND METHODS: Retrospectively, we conducted a review of unenhanced CT scans of 67 victims of violent deaths with thoracic injuries and compared CT findings with the results of clinical autopsy. Our gold standard was a comparison of CT scans with autopsy discussed in a monthly forensic radiology multidisciplinary team meeting (MDTM). The data were collected by organ system: heart, pericardium, aorta, lungs, pleura, bone, and diaphragm and performance indices (sensitivity, specificity, accuracy) were calculated. RESULTS: Pleural (59/67) and bone (55/67) injuries detected on CT were also found at autopsy and confirmed by the MDTM (sensitivity and specificity 100%). Seventeen out of 67 diaphragmatic lesions were visible on CT. Eighteen out of 67 were confirmed during MDTM after autopsy, yielding overall sensitivity of 94% and specificity of 98%. Forty out of 67 lung contusions were found on CT with two false positives and one false negative yielding 95% sensitivity for CT with a specificity of 96%, and accuracy of 95%. Fourteen out of 67 aortic injuries were found on CT compared to 19 confirmed during MDTM (sensitivity 74%, specificity 85%, accuracy 82%). In terms of pericardial lesions, 19/67 were found on CT and 20 on autopsy and confirmed during MDTM (sensitivity 80%, specificity 94%, accuracy 85%). Ten out of 10/67 cardiac lesions were visible on CT imaging and 15 found on autopsy and confirmed during MDTM (sensitivity 57%, specificity 94%, accuracy 81%). CONCLUSION: Unenhanced post-mortem CT performs well to detect pleural, pulmonary, bone and diaphragmatic injuries but less well to identify cardiac and aortic injuries, for which the use of indirect signs is essential.

Simultaneous CT angiography and whole-body CT is an effective imaging approach before multiorgan retrieval.

PURPOSE: To assess the role of whole-body computed tomography (CT) for determining morphological suitability before multiorgan retrieval (MOR) in brain dead patients. MATERIALS AND METHODS: Fifty-one clinically brain dead patients (21 women, 30 men; mean age 61 year±15) were included in this prospective, single center study. All patients had CT angiography of the brain and whole-body CT examination. CT images were evaluated for the presence of morphological abnormalities of lungs, liver and other abdominal organs and presence of vascular anatomical variants. The results of CT examinations were compared to intraoperative findings observed during organ harvesting and/or the results of histopathological analysis of biopsy specimens. The impact of whole-body CT examination on the harvesting process was evaluated. RESULTS: Ninety-five percent of vascular anatomical variants that were found intraoperatively were depicted on CT. CT density measurements predicted surgical finding of steatosis in 80% of patients. Whole-body CT changed the MOR strategy in 21/51 patients (41%) including 3 MOR cancellations and 8 grafts refusals, whereas organ harvesting was continued in 10 patients after histopathological analysis was performed. CONCLUSION: Selection of potential graft donors using whole-body CT is reliable and improves graft selection during MOR.

Osteoprotegerin levels are associated with liver fat and liver markers in dysmetabolic adults.

AIM: This study aimed to determine the association between visceral adipose tissue (VAT), liver fat (LF) content, and other markers of the metabolic syndrome (MetS) and osteoprotegerin (OPG) in dysmetabolic adults. METHODS: Subjects from the NUMEVOX cohort were included if they fulfilled at least one MetS criterion. They then underwent a thorough metabolic and cardiovascular evaluation, including arterial stiffness, atherosclerotic plaques, homoeostasis model assessment for insulin resistance (HOMA-IR) indices and OPG. VAT and LF content were measured by magnetic resonance imaging (MRI). Ultrasound examination of arteries and arterial stiffness were recorded, and age- and gender-adjusted paired correlations calculated. RESULTS: Body mass index, waist circumference and MRI-derived VAT correlated with OPG, whereas abdominal subcutaneous fat did not. OPG levels were strongly correlated with LF content (r=0.25, P=0.003), liver markers such as alanine aminotransferase (r=0.39, P<0.001) and HOMA-IR index (r=0.39, P<0.0001). Plasma OPG also correlated with arterial stiffness and the number of atherosclerotic sites. CONCLUSION: Plasma OPG levels are positively associated with both liver markers and increased LF content, but not with subcutaneous fat in dysmetabolic men. These findings suggest that elevated OPG levels may play a role in the link between fatty liver disease and enhanced cardiovascular risk.